Contact element assembly including positioning means



1966 B. s. BENGTSSON 3,236,987

CONTACT ELEMENT ASSEMBLY mownme POSITIONING MEANS .F'iled June 11, 1963 2 Sheets-Sheet 1 INVENTOR I 6597/1. 5. BIA/671550 BY r @0124, 4%mu-r/azm ATTORNEYS Feb. 22, 1966 B. s. BENGTSSON 3,236,987

CONTACT ELEMENT ASSEMBLY INCLUDING POSITIONING MEANS Filed June 11, 1963 2 Sheets-Sheet 2 INVENTOR. Berfil S.Beng1sson Moses,Mc Glew 8 Toren ATTORNEYS.

United States Patent 3,236,987 CONTACT ELEMENT ASSEMBLY INCLUDING POSITIONING MEANS Bertil S. Bengtssou, Scituate, Mass., assignor to Sigma Instruments Inc., a corporation of Massachusetts Filed June 11, 1963, Ser. No. 287,039 Claims. (Cl. 200-166) This invention relates in general to a spring or plate pile-up or assembly and to an improved method of assembling multiple thin plates or spring contacts for use in relays, switches, terminal blocks and the like. It also relates to an improved contact construction in which a substantially rigid base plate or bracket is provided carrying a flexible and resilient contact-carrying member or tongue so constructed as to have a maximum bendable length. The base plate members can be assembled and locked in spaced relationship without interference with the retention of the yieldability and flexibility of the contact-carrying elements throughout the greater part of their lengths.

The present invention has particular application for the construction of multiple switches which include a plurality of terminals or contact elements which are arranged in a block assembly with predetermined spacing for effecting a series of contacts in accordance with the operation of the switch means. It is. essential with arrangements of this nature that the contacts or terminal elements are arranged in a pile-up or assembly with the spacing therebetween accurately maintained even after long periods of use. Devices of this character should be capable of manufacture at extremely low cost.

Prior to the present invention, contact assemblies or pile-ups have usually been accomplished by employing insulator separators for spacing the contact springs or plates apart. A disadvantage in the employment of such a method is that if a pile-up of alternate layers of insulation and plates is made, normal manufacturing in the thickness tolerances of the insulation or of the contact plates will be cumulative. Thus it is essential that the thickness of the insulators and plates be controlled within exact limits which is impractical or impossible. In addition, the insulation material suitable for, this application may dry out or absorb moisture and with changes in the surrounding atmosphere the separators will expand and contact. Such movement will eventually result in the loosening of the terminals or contacts or in the breaking of the securing screws -for holding the pile-up together.

In accordance with the present invention there is provided an improved pile-up assembly which includes one or more comb elements having a plurality of notches defined thereon at predetermined intervals which may be uniform or not as required. The comb elements are adapted to be positioned within openings in the plates or contact elements and each plate is aligned with a respective notch of the comb elements and held thereby. The assembly is completed by means for moving a comb element laterally or spacing the comb elements apart if a pair of opposed comb elements is used, preferably by the employment of a pair of complementary shaped wedge elements which are also inserted into the openings of the plates and moved together to urge the comb elements to separate and cause the comb elements to engage around each of the plates at the respective notches and to anchor them tightly in a-correctly spaced position. An advantage of a construction of this type is that the notches may be easily cut or milled into the comb elements in one operation and there is no"- accumulation of dimensional errors which is true in the case of the stack of plates and insulation separators. A further advantage is 3,236,987 Patented F eb. 22, 1966 'that the construction is not subject to the elfects of atmospheric conditions in respect to the spacing of the contact elements e.g., insulating layers and it thus provides a stable contact assembly. In addition, the method is simple and requires a minimum expenditure for assembly fixtures and may be easily effected in a very rapid manner.

Accordingly, it is an object of this invention to provide a contact or spring element pile-up assembly for relays, switches, terminal blocks, and the like, which includes a comb element or a pair of opposed comb elements having notches in their outwardly extending edges which receive and hold contact elements in a pile-up, and when pairs of comb elements are used further including means for spacing the comb elements, such means being preferably wedge elements which are inserted between the comb elements and shaped so that the complete insertion of the wedge elements from opposite directions causes outward positioning of the comb elements in a complete and stable contact assembly.

A further object of the invention is to provide a contact assembly as set forth herein which is simple in design, rugged in construction and economical to manufacture.

A further object of the invention is to provide an improved contact element characterized by a base or bracket plate which may be assembled with other elements in accordance with the methods described or in -any other suitable manner and which carry long flexible contact elements not constrained by the manner of mounting the base or bracket plates. Such contact elements may be made operatively bendable throughout practically their entire lengths instead of being held rigid .throughout a substantial part of their lengths by the means for supporting the pile-up.

For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

In the drawings:

FIG. 1 is a perspective view of one form of a conductor plate or contact element which may be employed in a pile-up or assembly constructed in accordance with the lnvention;

FIG. 2 is a perspective view of a plate holding comb;

FIG. 3 is a side elevation of, an assembly of plates or pile-up;

FIG. 4 is an enlarged section online 4-4 of FIG. 3;

FIG. 5 is a side elevation of a pile-up of base or bracket plates each having a long flexible contact finger welded thereto;

FIG. 6 is an enlarged section on line 6-6 of FIG. 5; FIG. 7 is a transverse section taken on the line 7-7 of FIG. 6, showing portions of a comb and bracket plate and contact finger;

' FIG. 8 is a perspective view of one of the bracket plates with the long contact finger attaching thereto; and,

FIG. 9 is a perspective view of a jig or fixture for assembling pile-up, a pile-up being shown, partly assembled, portions of the combs being broken away.

I Referring to the drawings in particular, the construction shown includes a plate or contact element, generally designated 10 which has an elongated opening or slot 12 which preferably terminates in Wedge-shaped or tapered ends 14. -In accordance with the invention, the contact elements 10 are arranged in predetermined space relationship. This is advantageously done by means of a jig 15 having elongated parallel grooves 16'defined therein at predetermined spaced locations, into which the plates or contact elements are positioned. With the contact elements spaced in this manner, comb elements designated 18 and 19 are employed for assembling the contact elements 10 in a permanent pile-up in their spaced relationship.

The comb elements are formed of rigid insulating or dielectric material, for example, wood, vulcanite or a plastic which will retain its shape and dimensions indefinitely. Various plastics may be used, for example, a thenmo setting phenolic plastic such as Bakelite. Such a plastic molded with a linen or paper base is very servicable.

Another very satisfactory material is hard, fine-grained wood such as, for example, mahogany, the grain of which runs longitudinally of the combs. V

The comb elements 18 and 19 advantageously include a straight or flat side 20 and a side 22 into which are cut parallel slots or notches 24 at predetermined spaced locations. The spacing of the slots may be uniform or varied depending on the spacing of the plates or contact members desired.

The comb elements are inserted into the openings 12 of the elements 10, and if a pair of notched combs is used their edges 22 are placed in opposite directions outwardly, so that the notches 24 of opposing comb elements engage around the element 10 at respective ends of the slot 12.

After the combs are alignedin this manner, means such as wedge elements 28 are employed to effect the separation of the combs in opposite directions for the purposes of permanently aligning and holding the elements in the pile-up. The wedge elements 28 are urged in opposite directions, as indicated by arrows 32, to cause the outer surfaces of the wedge elements to move the respective comb elements 18 and 19 outwardly into tight engagement with the contact elements 10. In FIG. 3 the wedge elements 28 are indicated in the final assembled position. The wedge elements are also preferably made of an insulating material, although this is not essential if they are shaped so as not to contact the edges of the slots in the contact elements, but bear only upon the inner surfaces of the combs. The wedges are preferably made of similar material to the combs with which they are used, although this is not essential.

The combs are preferably forced apart by the wedges so that they enter the tapered or wedge-shaped portions of the slot ends. The Walls of these inclined end portions then cut into the'surfaces of the combs more or less so that there is a positive interlock between the corners of the slots inthe plates and the material of the combs. This makes for very firm and positive engagement.

FIG. 9 shows how the plates may be readily assembled by means of the jig or fixture 15. This has a transverse channel 34 in its upper surface. The contact plates are placed in the slots 16 and the combs 18, 19 passed through the slots in the plates. The wedges 28 are then driven in so as to separate the combs and cause them to tightly engage the plates. The pile-up assembly is now complete and may be lifted out of the fixture.

FIGURES 5, 6, 7 and 8 show a novel construction of contact members which may be incorporated in spring pile-ups and is particularly adapted'for use in connection with the pile-up construction and method already described, although the improved contact members may be mounted in any other suitable manner. In accordance with this construction each contact member includes a base plate or bracket 40 and a flexible contact spring or finger 42 which is fixed to the base plate 40 near one end thereof as indicated at 44, by welding, soldering or in any other suitable manner. The flexiblev member- 42 extends lengthwise of the base plate and may extend beyond the base plate as indicated by the portion 46. This end is suitably formed to provide a contact member as by having attached' thereto a contact button 48. The base plates or brackets 40 are then mounted in a pile-up as by the use .of thecombs 18, 19 and wedges 28, extending through the slots 12 in the base plates. The flexible members 42 are also provided with slots 50 through which the combs and wedges extend, the slots 50 being longer and wider than the slots 12, so that they do not engage the combs or wedges but are free to be bent from their points of connection 44 with the base plates as indicated by the dotted lines in FIGURE 5. The flexible contact members 42, owing to this length have much greater flexibility than the contact members here to fore commonly employed, bendable only from the position where they were clamped by the holding means. For example, if the contact members were bent only from the points where they were clamped by the comb member 19 the bendable length would be only that portion indicated by the bracket A in FIG. 5. On the other hand, utilizing the same clamping means for holding the bracket plates 40, the contact fingers 42 would be bend-able through a length indicated by the bracket B in FIG. 5 which may be two or more times the bendable length of the contact members mounted in the old way. Greater flexibility is obtained while still using a much thicker material for the contact fingers 42 than would be usable for the contact members 10. The use of excessively thin contact blades may be thus avoided. The long flexible contact fingers are bent less sharply at their points of attachment to the bracket plates than would be required if the bendable portions of the elements were shorter so that there is less metal fatigue and the fingers have longer life. The thicker metal also gives the finger greater stability for resisting stress and maintains better contact alignment.

The thicker metal also gives the fingers greater conductivity and thereby reduces the internal resistance of the relay or switching device.

The contact fingers may be bent so as to have a set towards the base plates so that they will normally bear against the base plates before they are stressed by their operating means.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A contact assembly comprising a plurality of contact elements, each having a slot therein, the slots of all of said elements being aligned, a first comb element having contact element positioning notches defined at predetermined spaced intervals along an edge thereof and positioned to extend through the slots of all of said contact elements with contact elements engaged in respective notches of said comb elements adjacent one of the ends of the slots of said contact elements, a second comb having notches therein defined at spaced intervals along an edge thereof and positioned to extend through the slots of all of said contact elements with the contact elements engaged in respective notches of said second comb adjacent the opposite ends of the slots of said contact elements, said first and second comb elements having walls bounding the notches therein which limit the lateral movement of said contact elements in each lateral direction and prevent said contact elements from moving together into contact, and means located between said'first and second comb elements, holding said comb elements in tight engagement with said contact elements at respective opposite ends of the slots defined therein,

2. A contact assembly comprising a plurality of contact elements, each having a slot therein, the slots of'all of said elements being aligned, a first comb element having notches defined at predetermined spaced intervals along an edge thereof and positioned to extend through the slots of all of said contact elements with contact elements engaged in respective notches of said comb elements adjacent one'of the ends of the slots of said contact elements, a second comb having notches therein defined at spaced intervals along an edge thereof and positioned to extend through the slots of all of said contact elements with the contact elements engaged in respective notches of said second comb adjacent the opposite ends of the slots of said contact elements, and means located between said first and second comb elements holding said comb elements in tight engagement wtih said contact elements at respective opposite ends of the slots defined therein, including separate wedge elements having inclined faces which are juxtaposed.

3. A contact assembly according to claim 1, in which the comb elements are of insulating material.

4. A pile-up assembly of thin plates, each having a slot therein, the slots of all of said plates being aligned, a comb element of insulating material having plate element positioning notches therein located in predetermined spaced relationship along an edge thereof and positioned to extend through the slots in the plates, said comb element having walls bounding the notches which limit the lateral movement of said plates in either direction and prevent said plates from moving together into contact, and means urging said comb element to the end of the slots of said plates and for holding the comb element in interlocking relationship with said plates with portions of the plates fitting in the notches.

5. A contact assembly comprising a plurality of contact elements, each having a slot therein, the slots of all of said elements being aligned, a first comb element having notches defined at predetermined spaced intervals along an edge thereof and positioned to extend through the slots of all of said contact elements with contact elements engaged in respective notches of said comb elements adjacent one of the ends of the slots of said contact elements, a second comb having notches therein defined at spaced intervals along an edge thereof and positioned to extend through the slots of all of said contact elements with the contact elements engaged in respective notches of said second comb adjacent the opposite ends of the slots of said contact elements, and means located between said first and second comb elements, holding said comb elements in tight engagement with said contact elements at respective opposite ends of the slots defined therein, said comb elements being forced into engagement with the notches to an extent suflicient to cause the material of the notches to cut into the material of the comb elements.

6. A contact assembly comprising a plurality of elements, each of which comprises a base plate having an elongated slot therein and a flexible contact finger having an elongated slot therein of larger dimensions than the slot in the base plate but extending thereover, means for securing the flexible contact finger to the base plate near one end of said slot and a contact formation on the free end of said flexible finger remote from the position where the flexible finger is attached to the base plate; a comb member extending through the slots in the base plates and flexible contact fingers, said comb member having longitudinally spaced notches therein, and means for holding said comb member in engagement with the ends of the notches in the base plates at at least one end thereof so as to hold the base plates in predetermined spaced relationship, said comb member extending through the holes in the flexible contact fingers which are free to bend from their points of attachment to the base plates.

7. A contact assembly comprising a plurality of contact elements each of which consists of a base plate and a long flexible contact finger secured to the base plate near one end thereof and extending lengthwise of the base plate and having a contact formation beyond the opposite end of the base plate from that to which the end of the contact finger is secured, and means engaging the base plates for holding them firmly in a contact pile-up, the flexible contact finger of each of said contact elements being free from engagement with said base plate holding means.

8. A switch contact blade comprising a base plate having a longitudinal slot therein, and a long flexible contact finger secured to the base plate near one end thereof and extending lengthwise of the base plat and having a contact formation beyond the opposite end of the base plate from that to which the end of the contact finger is secured, said contact finger having a longitudinal slot therein registering with, but larger than the slot in the base plate, and securing means extending through said base plate and said contact finger slots engaged with said bas plate and clearing said contact finger.

9. A switch contact blade as claimed in claim 8 in which the end of the contact finger secured to the base plate is offset from the flexible body of the finger, said flexible finger being bent so as to yieldingly press against the side of the base plate.

10. A contact pile-up comprising a plurality of slotted contact elements and a comb having a side with a plurality of spaced plate elements positioning notches formed therein, the comb extending through the slots of said contact elements with the notches engaging the respective elements, said comb having walls bounding the notches which limit the lateral movement of said plates in either direction and prevent said plates from moving together into contact, and means for urging said comb to the end of the slots of said plates and for urging the comb into tight engagement with the contact elements.

References Cited by the Examiner UNITED STATES PATENTS 2,638,514 5/1953 Martin 200166 X 2,779,843 I/ 1957 Wiberg 200166 2,799,754 7/1957 Montchausse et al. 200166 2,939,937 6/1960 Rejdin et al 200-166 KATHLEEN H. CLAFFY, Primary Examiner, ROBERT K. SCHAEFER, Examiner, 

10. A CONTACT PILE-UP COMPRISING A PLURALITY OF SLOTTED CONTACT ELEMENTS AND A COMB HAVING A SIDE WITH A PLURALITY OF SPACED PLATE ELEMENTS POSITIONING NOTCHES FORMED THEREIN, THE COMB EXTENDING THROUGH THE SLOTS OF SAID CONTACT ELEMENTS WITH THE NOTCHES ENGAGING THE RESPECTIVE ELEMENTS, SAID COMB HAVING WALLS BOUNDING THE NOTCHES WHICH 